A couple points.
Pro #1 for sony is really not correct. It's just tools like calibre work so well, since it can easily convert almost any format to LRF the conversion is almost seamless. So it gives the appearance that SONY supports any format. However the same can be achieved for the Kindle with tools like MobiPerl (lit2mobi) and MobiCreator.
Also on your Kindle Con #3 the same applies for the SONY.
Also you might want to add as a pro for kindle the fact that you can annotate and have a built in dictionary.
For me the question comes down to form vs content (ease of buying/installing it)
Personally I really like my SONY device, it is very ergonomic and the design is quite elegant and very portable, I carry this device everywhere with me. It fits easily in most large pockets. The community support is by far the best and is the only non PC device that supports secure PDF.
What the kindle has is content. Not only does it have the most selection, it also has the best prices. There might be a few exceptions but most of the time Amazon will be cheaper.
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